[vtkusers] How to resample RT Dose Grid pixel data with respect to a CT image?

Jothybasu Selvaraj jothybasu at gmail.com
Tue Oct 9 07:05:26 EDT 2012


VTKImageData's first pixel is on the lower left bottom, while the
DICOM's first pixel is on the top left.

Why can't you use vtkDICOMImageReader?



On Tue, Oct 9, 2012 at 12:02 PM, Abhishek Gupta <abhishek at meddiff.com> wrote:
> I am using python's VTK wrapper. Python's dicom library to read dicoms and
> wxPython to display images.
> Here's the code that I am using:
> ****************************************************
> dataArray = vtk.vtkUnsignedIntArray()
> for pixel in grid.flat:
>     dataArray.InsertNextValue(pixel)
>
> imageDataArray = vtk.vtkImageData()
> imageDataArray.SetDimensions(no. of rows, no. of columns,1)
> imageDataArray.SetSpacing(2.5,2.5,1)
> imageDataArray.GetPointData().SetScalars(dataArray)
> imageDataArray.Update()
>
> contours = vtk.vtkContourFilter()
> contours.SetInput(imageDataArray)
> contours.GenerateValues(1, level,level)
> contours.Update()
> ****************************************************************
>
>
>
>
> On Tue, Oct 9, 2012 at 4:27 PM, Jothybasu Selvaraj <jothybasu at gmail.com>
> wrote:
>>
>> If you are dealing with DICOM objects in vtk, make sure you are using
>> "FileLowerLeftOn" in the vtk readers.
>>
>> Are you using vtkImageViewer2 for viewing the images?
>>
>>
>>
>> On Tue, Oct 9, 2012 at 11:48 AM, abhishek <abhishek at meddiff.com> wrote:
>> > Hello Jothy,
>> >
>> > Red color structure is at the correct location, which is what I wish to
>> > achieve. The structure generated by my code is displayed in blue color.
>> >
>> > Regards,
>> > Abhishek Gupta
>> >
>> > -----Original Message-----
>> > From: Jothybasu Selvaraj [mailto:jothybasu at gmail.com]
>> > Sent: Tuesday, October 09, 2012 2:44 PM
>> > To: abhishek
>> > Subject: Re: [vtkusers] How to resample RT Dose Grid pixel data with
>> > respect
>> > to a CT image?
>> >
>> > As far as I understand, even if you don't resample your dose grid still
>> > it
>> > should be overlaid properly (unless both have different frame of
>> > reference).
>> >
>> > Could you send apicture of of you get?
>> >
>> > If required you could resample your dose grid using vtkImageResample and
>> > don't forget to update the image attributes using
>> > vtkImageChnageInformation!
>> >
>> > Jothy
>> >
>> >
>> >
>> > On Tue, Oct 9, 2012 at 7:30 AM, abhishek <abhishek at meddiff.com> wrote:
>> >> Dear Users,
>> >>
>> >> I want to draw ISODOSE contours on a CT Image. To generate ISODOSE
>> >> contours, I am using vtkContourFilter class.
>> >> I am using RT DOSE Grid's pixel data to create vtkImageData and giving
>> >> the resulting vtkImage as input to vtkContourFilter.
>> >>
>> >> My problem is that, the RT DOSE Grid's and CT image's pixel spacing
>> >> and image patient position(IPP) are different. This result's in
>> >> generation of wrong contour points.
>> >>
>> >> For reference IPP and Pixel spacing for CT and RT DOSE grid are:
>> >> CT:    [-329.6, -319, -241.3], [1.2461, 1.2461]
>> >> Dose: [-185.1, -180, -546.3], [2.5, 2.5]
>> >>
>> >> I have two questions here:
>> >> 1. I am certainly sure that I will have to some how resample dose's
>> >> pixel data to map on to CT image. How can I do this?
>> >>
>> >> 2. Will vtkImageResample class be useful? If yes, then how can I use
>> >> this class. If no, then what other options do I have?
>> >>
>> >> Regards
>> >> Abhishek.
>> >>
>> >>
>> >>
>> >> --
>> >> View this message in context:
>> >> http://vtk.1045678.n5.nabble.com/How-to-resample-RT-Dose-Grid-pixel-da
>> >> ta-with-respect-to-a-CT-image-tp5716546.html
>> >> Sent from the VTK - Users mailing list archive at Nabble.com.
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>> >
>> >
>> > --
>> > Jothybasu Selvaraj
>> > PhD Student
>> > University of Liverpool
>> > UK
>>
>>
>>
>> --
>> Jothybasu Selvaraj
>> PhD Student
>> University of Liverpool
>> UK
>
>



-- 
Jothybasu Selvaraj
PhD Student
University of Liverpool
UK



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